Abstract

Types of NADPH-d+ neurons (Vincent et al., 1983) were identified in the striatum and basolateral nuclei of the amygdala; striocortical neurons were detected in the striatum using the DiI marker (Belichenko and Dahlstrom, 1995). NADPH-d+ cells were numerous. Staining of these cells and all their processes, along with our previous studies of the neurons in these formations in the human brain using the Golgi method, allowed us to identify their shapes and identify them as sparsely or extensively branched cells. The main efferent neurons of the striatum and basolateral amygdala (extensively branched medium spiny cells and bushy spiny cells respectively) and their extensively branched interneurons did not contain NADPH-d. Efferent NADPH-d+ neurons included reticular, sparsely branched cells with long dendrites, which were the most numerous cells in both formations, as well as occasional large multipolar branched neurons; the striatum also contained numerous sparsely branched short-dendrite cells (a neuron type most represented in the brainstem and especially the reticular formation). Projections of reticular cells from the striatum to the cortex were demonstrated. NADPH-d+ interneurons were sparsely branched: in the striatum, these were slender, long-dendrite, bipolar cells (numerous), ordinary bipolar cells, twisted and large dendrite-poor cells; the amygdala contained the same bipolar cells along with radial neurons. Thus, NADPH-d+ neurons in these formations were more ancient, i.e., structurally less complex, cell types.